I would start out small if its your first time. try 25-30 and see how that is for you. then go up to what you can tollerate. I am pretty tollerant myself of T3 & T4 so I can use a higher dose but no 2 people are alike.
For instance a little clen maybe 50 mcg a day has me wired like crazy and others can take 100-200 and be fine. Of course clen is a little different since you can build quite a tollerance to it if you use it for more than 2-3 weeks